Custom ramdisk

Tim Komarov happycorsair at yandex.ru
Mon Mar 31 18:07:34 CEST 2014


Hello, L4 hackers!

I use Pandaboard for my practising with Fiasco.OC and L4Linux.

1) I got a problem with booting L4Linux with my own ramdisk. When I use 18 mb ramdisk, I got the following error:

reading image.elf                                                               

24691072 bytes read                                                             
## Starting application at 0x81000000 ...
...
,,,[Everything is usual]
,,,

NET: Registered protocol family 17                                                       
List of all partitions:                                                                  
No filesystem could mount root, tried:  ext3 ext2 ext4 cramfs                            
Kernel panic - not syncing: VFS: Unable to mount root fs on unknown-block(1,0)           
CPU: 0 PID: 1 Comm: swapper Not tainted 3.13.0-l4 #1                                     
[<0200c624>] (unwind_backtrace+0x0/0xec) from [<020054c0>] (show_stack+0x10/0x14)        
[<020054c0>] (show_stack+0x10/0x14) from [<0222e63c>] (panic+0x7c/0x1b8)                 
[<0222e63c>] (panic+0x7c/0x1b8) from [<022f2c40>] (mount_block_root+0x25c/0x29c)         
[<022f2c40>] (mount_block_root+0x25c/0x29c) from [<022f2f44>] (prepare_namespace+0x160/0)
[<022f2f44>] (prepare_namespace+0x160/0x1b4) from [<022f2894>] (kernel_init_freeable+0x1)
[<022f2894>] (kernel_init_freeable+0x174/0x1b8) from [<0222ccf0>] (kernel_init+0x8/0x118)
[<0222ccf0>] (kernel_init+0x8/0x118) from [<020077d4>] (ret_from_fork+0x14/0x20)         
[<020077d4>] (ret_from_fork+0x14/0x20) from [<00000000>] (  (null))                      
panic: going to sleep forever, bye         

To make ramdisk I simply create a file, write 18 Mb of zeroes to it (with dd), create in that file ext2 partition and copy there files from ramdisk-arm.rd

So, what should I do to get a proper working ramdisk?

2) Even more. If I create 20 mb ramdisk, I got this:

reading image.elf                                                                        

26788224 bytes read                                                                      
## Starting application at 0x00000000 ...  

Than the booting hangs. Why so? 

Looking forward for your help, guys!

Best wishes,
Tim



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